If the nut face of the adapter is touching the face of the carb inlet, you can't strip the threads.
My opinion is that if it does not leak at the fitting pretty quick, it is coming from elsewhere... and it would not be on the upper air horn. If wind blew it there from a fitting leak you would also see lots of gas on top of motor.
If you are using the proper pressure fuel pump, it's a throttle bushing, gasket leak. If you are over pressurizing with electric fuel pump or ? then you are forcing gas out somewhere. Wait for Carb King to comment. He is the expert here.
It is pretty much necessary for you to discover exactly where the leak is coming from. Drive-inspect, drive-inspect....or let it run in the driveway and watch. Gotta know that. Show a pic of where on the upper section it is pooling/leaking/wet. How much of a leak are we talking after a few miles? On your drive, do you stop a leave motor running, wipe all the gas off and watch?
Can't see the inlet face of the carb you are using. That face has to be flat and perpendicular to threads or needs washered. Maybe the seal is done at the nose of the adapter fitting. I'm not sure.
